The symbol used for forex quotes is, in ISO codes, "currency1.currency2" (e.g. GBP.USD)
and the quote will be returned as a rate expressed as currency1/currency2. BidPx (132) indicates the rate at which the broker is willing to buy
currency1 and deliver currency2, OfferPx (133) indicates the rate
at which the broker is willing to sell currency1 and receive currency2. Indicative rates
are quoted in the BidPx (132) field and may contain a level in
the BidSize (134) field.